Closure cp for a motor vehicle radiator

ABSTRACT

A closure cap ( 10 ) for a fixed neck of a motor vehicle radiator is provided with a cap outer part ( 12 ), which comprises a closure element ( 17 ) that can be joined to the reservoir neck, and comprises a grip element ( 13 ) that is held in a manner that permits it to he twisted in relation to the closure element. A torsional stop ( 20 ) is provided between said closure element and grip element. The aim of the invention is to provide a closure cap of the aforementioned type with safety-relevant functions of the torsional stop and of the reduction of excess pressure in a structurally simple manner whereby permitting them to be exactly adapted to one another. To this end, an actuator ( 15 ) that can be expanded when subjected to heat is provided both for axially engaging and disengaging the coupling insert ( 46 ) of the torsional stop ( 20 ) as well as for adjusting the pretension with which the valve body ( 22 ) of the valve arrangement ( 11 ) is pressed against the sealing seat ( 21 ).

[0001] The present invention relates to a closure cap for a fixed neckof a container, in particular a motor vehicle radiator, as genericallydefined by the preamble to claim 1.

[0002] In one such device, from German Patent Disclosure DE 197 53 597A1, the torsional stop between the closure element and the grip elementis formed by an axial coupling bolt, which is acted upon by a springassembly functioning as a function of temperature, while theprestressing of the reciprocating valve body of the valve assembly isadjustable under pressure control mechanically or by electric motor. Adisadvantage of this is that in such closure caps, the safety-relevantfunctions are performed by two differently designed and also differentlytriggered components. Not only does this mean complicated engineeringprovisions, but it also has the problem that the safety-relevantfunctions that respond to different reference variables can be adaptedonly very poorly to one another.

[0003] The object of the present invention is therefore to create aclosure cap of the type defined at the outset, with which thesafety-relevant functions of the torsional stop and of the overpressurereduction can be performed in a structurally simpler way and inparticular can also be more precisely adapted to one another.

[0004] For attaining this object, in a closure cap of the type definedat the outset, the characteristic recited in claim 1 is provided.

[0005] By the provisions of the invention, it is attained that a singlecomponent is provided for both securing against relative torsion and forvarying the overpressure reduction, leading to a structuralsimplification of the closure cap, and because of the single referencevariable used for performing the safety-relevant functions, thesefunctions are always adapted to one another.

[0006] Advantageous features of the actuator are disclosed by thecharacteristics of claim 2 or 3.

[0007] A structurally simple embodiment is obtained by thecharacteristics of claim 4, which moreover has the advantage that thereference variable, such as the temperature or pressure in thecontainer, can be picked up in a suitable way independently of theactuator. An advantageous heat transfer from the heating resistor to theactuator is obtained by the characteristics of claim 5.

[0008] Further advantageous features in terms of the disposition of theactuator and of an electronic triggering unit between the base value andthe actuator become apparent from the characteristics of claim 6, or oneor more of claims 7-10. The characteristics of claim 11 and claim 12show an embodiment of the connection between the valve body and theactuator, on the one hand, and between the torsional stop and theactuator, on the other.

[0009] Further details of the invention can be learned from the ensuingdescription, in which the invention is described and explained infurther detail in terms of the exemplary embodiments shown in thedrawing.

[0010] Shown are:

[0011]FIG. 1, in a schematic longitudinal section, a closure cap formotor vehicle radiators in a preferred exemplary embodiment of thepresent invention, in a first position, which is the position of reposeor outset position;

[0012]FIG. 2, in the left half of the section, a view corresponding toFIG. 1, and in the right half of the section in a second activeposition;

[0013]FIG. 3, in the left half of the section, a view corresponding toFIG. 1, and in the right half of the section in a third active position.

[0014] The closure cap 10 shown in the drawing in a preferred exemplaryembodiment has a overpressure valve assembly 11 inside a cylindricallyembodied inner part 14 and a torsional stop 20 between an outer part 12and a handle or grip element 13 that serves, via a male-threaded part17, to screw the closure cap 10 onto the opening of a neck, not shown,of a motor vehicle radiator or other container and to unscrew it again;both the overpressure valve assembly 11 and the torsional stop 20 aretriggered in such a way that on the one hand, the opening pressure ofthe overpressure valve assembly 11 and on the other the unlocking andlocking motion of the torsional stop 20 can be adjusted and assured bymeans of a single electrothermal actuator 15. The overpressure valveassembly 11 can be adjusted to an opening pressure that takes the motorvehicle radiator overpressure in normal operation into account and to anopening pressure that corresponds to the higher motor vehicle radiatoroverpressure that results from the dammed-up heat that develops when themotor vehicle engine is switched off. The adjustment of the torsionalstop 20 at normal pressure of the motor vehicle radiator, that is, oncethe coolant has cooled down, causes the torsional stop 20 to effect atorsion lock between the grip element 13 and the outer part 12, so thatthe closure cap 10 can be screwed on and unscrewed, while at motorvehicle radiator overpressure with the coolant thus hot, the torsionalstop undoes the torsion lock between the outer part 12 and the gripelement 13, so that to prevent the closure cap 10 from being unscrewed,the grip element 13 rotates idly relative to the outer part 12.

[0015] In the drawing, the inner part 14 can be inserted sealingly viaan O-ring 16, in a manner not shown, into the neck of the motor vehicleradiator or other container. It is understand that instead of beingprovided with a male-threaded 17, the outer part 12 can also be providedwith a bayonet mount.

[0016] The cylindrically embodied inner part 14 of the closure cap 10that is equipped with the overpressure valve assembly 11 has a bottom 18and, above the bottom, an inward-protruding annular edge 19, whose upperregion is provided with a sealing seat 21 for a valve body 22 of theoverpressure valve assembly 11. The valve body 22 is a part that ishat-shaped in the middle, and a sealing disk 26 rests on itscircumferential flange 24; the flange and disk are acted upon by acompression spring 28 or overpressure valve spring; on its other end,this spring is braced on a pressure sleeve 29 that is guided such thatit can be moved axially up and down in a guide part 31, having an axialstop 34 for the pressure sleeve 29, and rests on an adjusting ring 30resting on the actuator 15. Between the bottom 18 and the inner part 14,openings 32 pointing into the motor vehicle radiator or container areprovided. The inner part 14, on its outer circumference and opposite thesmaller-diameter guide part 31, also has an opening 33, whichcommunicates with the outside atmosphere. When the valve body 22 haslifted from the sealing seat 21, a fluidic connection between theradiator or container interior and the ambient air results.

[0017] Inside the overpressure valve body 22, a negative-pressure valvebody 36 is also provided, whose lower annular edge 37, because of acompression spring 38, is braced on the sealing seat 21 of theoverpressure valve body 22 inside the annular edge 19 of the bottom. Atappet 39 of the overpressure valve body 36 passes through thehat-shaped overpressure valve body 22 and protrudes past it; thecompression spring 38 is disposed between the tappet 39 and the top sideof the hat-shaped overpressure valve body 22.

[0018] The inner part 14 is suspended, relatively rotatably, by an uppercollar 41 in a lower extension 42 of a false bottom 43 provided with arecess 44 in the center, and both the pressure sleeve 29 and theadjusting ring 30 are disposed in this recess 44.

[0019] The electrothermal actuator 15 is disposed above the false bottom43; with its underside, it rests on the adjusting ring 30, and a slavingbracket 46 of the torsional stop 20 rests on its top. The slavingbracket 46, which is for instance an upside-down U but can also have twoU-shapes extending crosswise to one another, has claws, on its axiallydownward-pointing ends 47, and these claws engage recesses or engagenext to fixed extensions of the male-threaded part 17, and can bedisengaged therefrom. Since the slaving bracket 46 is connected to thegrip element 13 in a manner fixed against relative rotation, it ispossible in this way, depending on the axial position of the slavingbracket 46, to achieve a torsion lock between the grip element 13 andthe male-threaded part 17, or idle rotation of the grip element 13 abovethe male-threaded part 17. The slaving bracket 46, on its indentedcentral region 48 with which it rests on the bottom on the actuator 15,is acted upon on top by a compression spring 49, which is braced on itsother end on the grip element 13 and which is guided in an annularextension 50 of the grip element 13 that establishes thepositive-engagement connection with the slaving bracket. Between theslaving bracket 46 and the grip element 13, a retaining disk 51 is heldsealingly on the male-threaded part 17; the retaining disk 5 serves asan end stop for the slaving bracket 46, in its disengaged position.

[0020] The electrothermal actuator 15 is formed by an absorptionactuator, preferably a metal hydride actuator, or an expansion actuator,which is shown in the drawing in the form of a diaphragm capsule 55. Theactuator 55 has the property of expanding upon an increase intemperature and contracting to its original size again when thecorresponding temperature is reduced. For subjecting the diaphragmcapsule 55 to temperature, a heating resistor in the form of a PTCheating element 56 is disposed at one or more points on the underside ofthe diaphragm capsule 55. This PTC heating element 56 is disposed suchthat a heat transfer with the least possible loss takes place from thePTC heating element 56 to the diaphragm capsule 55. The diaphragmcapsule 55 is preferably embodied such that its axially central regionexpands axially relative to the grip element 13, or axially relative tothe adjusting ring 30 and pressure sleeve 29.

[0021] The PTC heating resistor 56 is connected electrically, in amanner not shown, to an electric controller 57 which is accommodated ona printed circuit board 58, which in the exemplary embodiment shown isaccommodated in the grip element 13, directly beneath its covering. Aplug socket 61 is secured to a circumferential region of themale-threaded part 17 of the closure cap 10, and its contacts, notshown, are connected electrically to the controlling circuit board 58.An adaptor cable that connects the electrical connection of thecontrolling circuit board 58, and thus of the actuator 15, to theapplicable control elements of the motor vehicle is connected to theplug outlet 61. For instance, the triggering of the actuator 15 iseffected by means of a temperature and/or pressure sensor, and thissensor picks up the temperature and/or pressure at the motor vehicleradiator container or the like.

[0022] The safety-relevant functions of the closure cap 10, in the formof adjusting the overpressure valve assembly 11 and adjusting thetorsional stop 20, are as follows:

[0023] In the outset position, with the engine not running and cold,shown in FIG. 1, the diaphragm capsule 55 is in its retracted normalposition, in which the slaving bracket 46 is pressed by the compressionspring 49 into a position that prevents relative torsion that bringsabout a torsion lock between the grip element 13 and the male-threadedpart 17. The overpressure valve assembly 11 is likewise pressed againstthe sealing seat in its outset position, that is, the overpressure valvebody 22 is pressed against the sealing seat by the compression spring 28which is normally or when installed prestressed, in such a way that theoverpressure valve body 22 will open at an overpressure of approximately1.4 bar.

[0024] When the motor vehicle engine is started, the coolant in theradiator warms up. Once the coolant reaches a temperature higher thanapproximately 89° C., for instance, the controller 57 on the circuitboard 58 becomes active; that is, current is delivered to the PTCheating element 56 to heat it, or the PTC heating element is connectedto voltage. Thus heat is transferred from the PTC heating element 56 tothe diaphragm capsule 55, so that the actuator is actuated, and thediaphragm capsule 55 expands axially. The two compression springs 28 ofthe overpressure valve assembly 11 and 49 of the torsional stop 20 thatare oriented counter to one another and both act on the diaphragmcapsule 55 are adjusted in such a way that the compression spring 49 hasa lesser spring force than the compression spring 28. The diaphragmcapsule thus expands counter to the pressure of the compression spring49 of the torsional stop 20 and accordingly moves the slaving bracket 46axially up to the stop of the retaining disk 51. The slaving bracket 46thus becomes disengaged from the male-threaded part 17, so that it is nolonger possible to open the closure cap 10 because the grip element 13is rotating idly relative to the male-threaded part 17. The openingpressure of the overpressure valve assembly 11 remains as it was.

[0025] Once the engine is switched off, the coolant temperature risesfrom residual heating action to over 120° C., for instance. Thisactivates a second regulating stage in the controller 57 on the circuitboard 58, so that an increased voltage is applied to the PTC heatingelement 56, or a greater flow of current is brought about. This meansthat the diaphragm capsule 55 expands further. Since the slaving bracket46 is pressed against the stop of the retaining disk 51 (FIG. 2, righthalf of the section) counter to the action of the compression spring 49,it is attained that, as shown in the right half section of FIG. 3, thecompression spring 28 of the overpressure valve assembly 11 is furtherprestressed. This prestressing of the compression spring 28 causes theopening pressure of the overpressure valve body 22 to be increased, forinstance to approximately 2.0 bar. This safety stage persists until suchtime as the coolant temperature has dropped, which affects thetriggering of the PTC heating element 56 and the heating and coolingdown of the diaphragm capsule 55.

[0026] In the exemplary embodiment shown, the controller 57 isaccommodated physically in the form of the circuit board 58 in the gripelement 13. In another exemplary embodiment, not shown, of the presentinvention, the controlling circuit board 58 is provided in the plugoutlet 61, or in a plug part of the adaptor cable, either near theclosure cap 10 or near the connection with the motor vehicle.

1. A closure cap (10) for a fixed neck of a container, in particular amotor vehicle radiator, having a cap outer part (12), which has aclosure element (17) that can be joined to a container neck and a gripelement (13) retained rotatably relative to it, between which atorsional stop (20) is provided that has a coupling insert (46), whichcan be axially engaged and disengaged with and from the closure element(17) and is held in the grip element (13) in a manner fixed againstrelative rotation, for connecting the closure element and grip elementin a way that is releasably fixed against relative rotation, and havinga cap inner part (14), which has a fluidic connection between thecontainer interior and the container exterior and a valve assembly (11)for enabling and blocking the fluidic connection, and a valve body (22)of the valve assembly (11) that can be moved back and forth is pressedtoward the container interior against a sealing seat (21) on the capinner part (14) with prestressing, in such a way that if a limit valueof the container interior pressure is exceeded it can lift from thesealing seat (21), characterized in that an actuator (15) that iscapable of expansion from heat is provided both for axial engagement anddisengagement of the coupling insert (46) of the torsional stop (20) andfor adjusting the prestressing with which the valve body (22) of thevalve assembly (11) is pressed against the sealing seat (21).
 2. Theclosure cap of claim 1, characterized in that the actuator (15) isformed by an electrically heatable element of expansion material.
 3. Theclosure cap of claim 1, characterized in that the actuator (15) isformed by an electrically heatable absorption actuator, preferably ametal hydride actuator.
 4. The closure cap of at least one of theforegoing claims, characterized in that the actuator (15) is inoperative communication with an electrical heating resistor (56),preferably a PTC resistor, whose trigger voltage is picked up by atemperature and/or pressure sensor associated with the container.
 5. Theclosure cap of claim 4, characterized in that the electrical heatingresistor (56) is located on the underside of the actuator (15).
 6. Theclosure cap of at least one of the foregoing claims, characterized inthat the actuator (15) is disposed inside the closure element (17),oriented toward the grip element (13).
 7. The closure cap of claim 4,characterized in that an electronic triggering unit (57, 58) is providedbetween the temperature and/or pressure sensor and the electricalheating resistor (56).
 8. The closure cap of claim 7, characterized inthat the electronic triggering unit (57, 58) is disposed in the gripelement (13).
 9. The closure cap of claim 7, characterized in that theelectronic triggering unit (57, 58) is disposed in a plug of anelectrical connecting line leading to the closure cap.
 10. The closurecap of claim 9, characterized in that the plug is connected to acounterpart plug (61) on the closure cap.
 11. The closure cap of atleast one of the foregoing claims, characterized in that the valve body(22) is prestressed, facing away from the actuator (15), by a spring(28) which is braced, on its end remote from the valve body (22), on apressure piece (29, 30) that in turn rests on the actuator (15).
 12. Theclosure cap of at least one of the foregoing claims, characterized inthat the torsional stop (20) has a bracket (46), which rests by springaction on the actuator (15) and has terminal prongs (47), which canbrought lockingly into an engagement with the male-threaded part (17)and can be released unlockingly.